The colonial building that has been converted into an office for former chief executive Tung Chee-hwa opens to the public for a one-off open house today. The white, two-storey building in Mid-Levels is government property and was built in 1905. It was turned into an office building for former chief executives last year and will be shared by Donald Tsang Yam-kuen when his term ends in 2012. After the decision to use the mansion for Mr Tung's offices was announced, heritage conservation groups pressed the government to drop the plan or to keep the site open for the public. There are no plans for future public open days. Admission is free but no more than 80 visitors will be allowed in at once to protect the old wooden floor. More than HK$2 million was spent renovating the grade-three building at 28 Kennedy Road. It was a meeting venue for the Sino-British Joint Liaison Group from 1993 to 1999. A grade-three listing means a building is of some merit but does not qualify for consideration as a monument. Lam Sair-ling, senior property services manager of the Architectural Services Department, said it was not easy refurbishing the house. 'It has been a challenge to preserve its old features while fitting in modern facilities, such as fire protection equipment, air conditioners and communication devices,' he said. Covering 3,660 sq ft, the house was originally owned by Banque de L'Indo Chine and served as a campus for schools after the second world war. It was leased to the Design Centre from 2002 to 2006 as an exhibition venue. Mr Tung began to use it in April, prompting questions about what work he would do there. The government said Mr Tung did 'promotional and protocol-related activities' in his office - receiving foreign dignitaries and delegations, giving interviews and taking part in speaking engagements. Three rooms on the second floor have been designated offices for former chief executives, and Mr Tung has taken one. The government has estimated that it will cost about HK$2.2 million a year to run - covering the wages of three secretarial and clerical staff and a driver, and operating expenses. Visitors today will get a chance to view some of the gifts Mr Tung has received from dignitaries. These include a hand-painted vase given by South Africa's president, Thabo Mbeki, when he was deputy president; a clock from former US secretary of state Henry Kissinger; and a soccer ball and jersey autographed by the Liverpool Football Club. It will be open from 10am to 5pm.